The present invention relates to an apparatus for recovering electrodeposited metal in the form of layers from basis metal electrodes. The present invention is particularly directed to recovering zinc from the aluminum cathodes commonly used in the electrowinning of zinc.
The method of recovering zinc of high purity by electrowinning requires that cathode plates and lead anodes be supported in electrolysis cells containing an appropriate zinc electrolyte. The usual cathode is commonly an aluminum base onto which the zinc is deposited. In such systems, the zinc deposit forms a layer which adheres to the aluminum cathode plate surface and this layer is detached to recover the zinc. Generally the zinc layer is detached by inserting a wedge like object between the metal layer and the aluminum cathode surface on which it adheres along an edge or at a corner of said metal layer to partially separate the zinc from the aluminum cathode surface approximately at the zinc/aluminum boundary. After this initial separation, the zinc deposit is peeled off in the form of a zinc layer. Such peeling operations have been carried out manually but various mechanical means have been devised wherein one cathode plate at a time has its surface layer or layers of metallic zinc removed. U.S. Pat. Nos. 3,689,396 and 3,847,779 for example, each disclose a mechanical apparatus which employs means to initiate separation and then uses a second separate and distinct means to complete the removal of the zinc layer from the basis metal cathode plate. However, as a consequence of one by one treatment of the aluminum cathode plates, the recovery rate of zinc layers is low, and this adds to the cost of the metal recovered. An apparatus for stripping coherent metal layers from a plurality of basis metal cathode plates simultaneously would therefore increase the productivity and lower the cost of recovering electrodeposited zinc or other like metal.